Title:
The First Billion Years project: birthplaces of direct collapse black holes

Abstract: We investigate the environment in which direct-collapse black holes may form
by analysing a cosmological, hydrodynamical simulation that is part of the
First Billion Years project. This simulation includes the most relevant
physical processes leading to direct collapse of haloes, most importantly,
molecular hydrogen depletion by dissociation of $H_2$ and $H^-$ from the
evolving Lyman-Werner radiation field. We selected a sample of pristine atomic
cooling haloes that have never formed stars in their past, have not been
polluted with heavy elements and are cooling predominantly via atomic hydrogen
lines. Amongst them we identified six haloes that could potentially harbour
massive seed black holes formed via direct collapse (with masses in the range
of $10^{4-6} M_{sun}$). These potential hosts of direct-collapse black holes
form as satellites and are found within 15 physical kpc of proto-galaxies, with
stellar masses in the range $10^{5-7} M_{sun}$ and maximal star formation rates
of 0.1 Msun/yr over the past 5 Myr, and are exposed to the highest flux of
Lyman-Werner radiation emitted from the neighbouring galaxies. It is the
proximity to these proto-galaxies that differentiates these haloes from rest of
the sample.